A mixer in particular a building material mixer in which a rapidly rotating worm screw is mounted in a trough

ABSTRACT

An improved building material mixer having a rapidly rotating worm screw mounted in a trough and a baffle plate disposed perpendicular to or at an angle to the worm screw is disclosed. A recirculation path for the building material is provided having a portion which is narrowed or constricted. Small friction plates may be fixed to the outer part of the worm screw.

lnventor Paul Augmt C. Qelarlles 1, lBarceIome tilspanien, Barcelona, 8 Appl. No. LAM Filed iieh. 2A, 1969 Patented Sept. 7, 1971 Priority Feb. 27, 196A Grainy 1F 16 32 4133.7

MlUtiEWt m IPAR'HCIUILAM A liNJlilLlDllNG MA'MEIRIIIAL MIXER 1N WlHIHClHl A litAlPmLY ROTATING WORM SCREW 11S MOUNTED 1N A TWUGM 3 Clleims, 1 10m lint. U Mme 5/1141 Field oi Swlreh 259/10, 25,

[56] References Cited UNITED STATES PATENTS 659,085 10/1900 Miller.... 259/10 1,728,411 9/1929 Howardm. 259/97 2,692,124 10/1954 Mendoza.. 259/97 2,731,247 1/1956 Hudry 259/97 Primary Examiner-Walter A. Scheel Assistant ExamineF-Alan 1. Canton AnomeyJeffers & Rickert t 11 ACT: An improved building material mixer having a rapidly rotating worm screw mounted in a trough and a baffle plate disposed perpendicular to or at an angle to the worm screw is disclosed. A recirculation path for the building material is provided having a portion which is narrowed or constricted. Small friction plates may be fixed to the outer part of the worm screw.

PATENTEUSEP 7:27: 3,503,55

INVENTORI By PAUL Auwf f- Attorneys MIXER IN PARTICULAR A BUILDING MATERIAL MIXER IN WHICH A RAPIDLY ROTATING WORM SCREW IS MOUNTED IN A 'lROlUGl'l Such mixers are intended for the intensive preparation of the binding agent and of the fine components.

Experiments have shown that cement, hydraulic lime and similar binding agents with the mixing processes in mixers known hitherto are not provided with water as far as into the core. Thereby the full possibility of the strength attainable with these binding agents is not utilized.

in general literature various suggestions have already been made in order to remove this inconvenience but these have, however, only in a very few cases led to some desired results.

The mixing tools must so operate that they exert a high pressure and high velocity on the material to be mixed. Thereby it is achieved that the cement granules are ground still finer. When this happens, in the first place the total surface area of the binding agent is greater and secondly the water can penetrate further into the individual granules. Boundary layer formations of foreign media between the individual materials are prevented and the materials are actually extremely intimately combined with one another. So-called turbine mixers consisting of a cylinder closed at the bottom and having near the lower end a rapidly rotating disc fulfill with correct construction the requirements for the high surface exposure of the binding agent. These mixers however have the drawback that they are charged and emptied with difficulty.

With these known arrangements the charging place is higher than the emptying place while it should be vice versa.

For removing these disadvanta es it has already been taken into consideration in a proposal not previously known, that an inclined trough may be used including a rapidly rotating worm wheel with upwardly extending conveying means, terminating at the upper end shortly before an inclined wall whereby between the end of the worm screw and the inclined wall an acute angle is formed which widens upwardly. By means of this construction an intensive mixing in the mixer is ensured.

It has however, for example, proved to be disadvantageous in these machines that the rapidly rotating worm screw, for example, at 900-1000 revs. per min. throws out a part of the deposited material again to the material supply opening. The construction of the discharge side also has in all known constructions of such mixing apparatus given rise to considerable difficulties.

Here the object is the removal of all aforementioned drawbacks in the simplest manner and to simplify and thereby improve the mixer in particular for building materials in which a rapidly rotating worm screw is mounted in a trough. For this, it has been proposed to dispose the baffle wall at an angle or perpendicularly to the worm screw.

it has however been proved that the material to be mixed is pressed upwards possibly already partly before the end of the worm screw. it is however undoubtedly important, for the material to be mixed, to pass through the area of the pressure screw and baffle wall.

in order to ensure this with certainty it is proposed according to the invention for the wonn screw to be covered in the middle area by a sheet metal plate. Thereby it is of advantage for the space above the worm screw also to be closed below by a sheet metal plate.

A further special construction according to the invention is seen in that in the space a narrowed point is provided which by frictional pressure effects a further improvement of the material to be mixed.

It is also of advantage for small friction plates to be fixed on the outer part of the worm screw. These grind down additionally the cement which comes between the plates and wall.

A further construction of the invention is seen in that the filling funnel is located with its lower outlet end just above the the advantage that upon opening the filling funnel the cement does not fall in all at once but is soand is conveyed forward.

lzed continuously by the worm screw Thereby accumulations when shaking in the cement are avoided.

The invention will be described in more detail with reference to the drawing which shows purely diagrammatically any desired embodiment. This drawing is a partial longitudinal cross-sectional view of the apparatus according to the present invention. Further features of the invention thus follow from the drawing and the description thereof.

On the shaft ii a rapidly rotating worm screw 2 and a pressure screw 3 are located. On the baffle wall 4 the material to be mixed (cement and water or the like) is conveyed upwards into the space 5.

in order to ensure an accurate guiding in the direction of the arrow of the material to be mixed, the worm screw is covered by a sheet metal plate 7 between the inlet 6 and the return of the material in the area of the baffle wall 4. Furthermore the space 5 is also bounded at the bottom with a metal sheet 8. A narrowed part 9 is provided inside the space 5 which by means of frictional pressure effects a further compressing and mixing of the material to be mixed.

Furthermore there are disposed on the outer part of the worm screw, friction plates 10 which additionally grind down the cement which comes between these plates and wall.

The filling funnel 11 is preferably led so far down that its lower opening almost reaches the upper edge of the worm screw 2. Thereby the cement does notfall all at once into the area of the worm screw but is continuously seized by the worm screw and conveyed forward. Accumulation thus practically cannot occur.

IClaim:

l. in a building material mixer having a rapidly rotating worm screw mounted in a trough, the improvement comprismg:

a baffle plate at one end of said worm screw for guiding the material to be mixed;

a plate covering the middle portion of the worm screw; and

means connecting the region of the said baffle plate with the region of the worm screw end remote from said baffle plate, said connecting means forming a recirculating space for the material, said recirculating space having a narrowed part of lesser cross sectional area than that of the remainder of the recirculating space.

2. The improvement of claim ll further comprising small friction plates fixed on the outer part of the worm screw.

3. The improvement of claim 11 further comprising a filling funnel located with its lower outlet end just above said remote end of the worm screw. 

1. In a building material mixer having a rapidly rotating worm screw mounted in a trough, the improvement comprising: a baffle plate at one end of said worm screw for guiding the material to be mixed; a plate covering the middle portion of the worm screw; and means connecting the region of the said baffle plate with the region of the worm screw end remote from said baffle plate, said connecting means forming a recirculating space for the material, said recirculating space having a narrowed part of lesser cross sectional area than that of the remainder of the recirculating space.
 2. The improvement of claim 1 further comprising small friction plates fixed on the outer part of the worm screw.
 3. The improvement of claim 1 further comprising a filling funnel located with its lower outlet end just above said remote end of the worm screw. 